Endometriosis, described as the ectopic growth of endometrial tissue, is a debilitating disease of reproductive age women. In North America, at least 5.5 million women are affected by endometriosis at any one time and estimates of the economic cost of treating this disease range from $1-20 billion annually in the United States alone. An emerging view is that a reduced endometrial responsiveness to progesterone (P4), a defect referred to as the endometriosis phenotype, may play a significant role in development and/or progression of endometriosis. Relative to this question, we have explored whether exposure to TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin or dioxin) promotes development of the P4- resistant, endometrial phenotype. During our past funding period, we utilized adult human endometrial cell and tissue culture models, a chimeric model of experimental endometriosis in immunocompromised mice and a murine model of early life TCDD exposure to examine the impact of this toxicant. Using human cells, TCDD exposure was found to disrupt the anti-inflammatory action of P4, leading to cellular changes that potentiated the invasive behavior of endometrial tissues in our experimental endometriosis model. Our murine model of early life toxicant exposure revealed that TCDD-mediated defects in uterine P4 sensitivity can indeed arise from a developmental exposure. Perhaps more significant, our murine model also revealed that early life toxicant exposure leads to a heightened sensitivity to inflammation for multiple generations in the absence of additional toxicant exposure. Taken together our studies strongly suggest that disrupting the anti-inflammatory action(s) of P4 during endometrial maturation is the key mechanism by which TCDD-like toxicants alter reproductive function and impact a woman's risk of developing endometriosis. Thus, therapeutic interventions which target inflammatory signaling may have significant efficacy in blocking TCDD-mediated development of the P4 resistant endometrial phenotype associated with endometriosis. To validate this appoach we will utilize in vitro and in vivo studies designed to prevent the development and progression of the endometriosis phenotype as well as prevent the transmission of this phenotype to future generations. We propose three Specific Aims: 1): To evaluate the therapeutic potential(s) of resveratrol (RES) and PGE2 signaling inhibitors to reduce TCDD mediated loss of P4 responsiveness in human endometrial cells.. 2): To evaluate whether the anti- inflammatory effect(s) of RES and PGE2 signaling inhibitors alone or in combination will limit TCDD- mediated growth of experimental endometriosis in our humanized Rag2?(c) mouse model. 3): To evaluate the ability of RES and PGE2 signaling inhibitors to restore uterine progesterone sensitivity and reproductive function in a novel murine model of early life TCDD exposure that exhibits an adult endometriosis-like uterine phenotype.